Mitochondrial DNA polymerase is heterotrimeric, consisting of a homodimer of accessory subunits plus a catalytic subunit. The protein encoded by this gene is the catalytic subunit of mitochondrial DNA polymerase. The encoded protein contains a polyglutamine tract near its N-terminus that may be polymorphic. Defects in this gene are a cause of progressive external ophthalmoplegia with mitochondrial DNA deletions 1 (PEOA1), sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO), Alpers-Huttenlocher syndrome (AHS), and mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE). Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008],MDP1, MIRAS, MTDPS4A, MTDPS4B, PEO, POLG1, POLGA, SANDO, SCAE,Endocrine & Metabolism,Epigenetics & Nuclear Signaling,Mitochondrial metabolism,Mitochondrial metabolism_Mitochondrial Biogenesis,Nucleotide metabolism,Nucleotide metabolism_Molecular processes,POLG